Conditions similar to those that led to 1930s drought

STATE COLLEGE, PA — Accu-Weather.com meteorologists have warned oceanic conditions similar to those that triggered the ruinous "Dust Bowl" drought again appear to be in place.

The exceptionally warm Atlantic waters that played a major role in the record-breaking 2005 hurricane season, coupled with cooler-than-normal Pacific waters, are weakening and changing the course of a low-level jet stream that normally channels moisture into the Great Plains.

Effects are starting to be felt in "America's breadbasket," as the southern Great Plains region is already suffering from higher temperatures and a prolonged lack of precipitation.

Fast forward to Bush press conference, August 2006: "No one could have predicted a major drought ... "

____________________________

Is America facing yet another dust bowl?

From the Morris Daily Herald
http://www.morrisdailyherald.com/main.asp?SectionID=1&SubSection
ID=58&ArticleID=17343&TM=57545.85

Conditions similar to those that led to 1930s drought

STATE COLLEGE, PA — Accu-Weather.com meteorologists have warned oceanic conditions similar to those that triggered the ruinous "Dust Bowl" drought again appear to be in place.

The exceptionally warm Atlantic waters that played a major role in the record-breaking 2005 hurricane season, coupled with cooler-than-normal Pacific waters, are weakening and changing the course of a low-level jet stream that normally channels moisture into the Great Plains.

Effects are starting to be felt in "America's breadbasket," as the southern Great Plains region is already suffering from higher temperatures and a prolonged lack of precipitation.

Why could a new Dust Bowl drought occur?

The low-level jet stream — a fast-moving current of winds close to the Earth's surface — travels from east to west across the Atlantic, then typically curves northward as it crosses the Gulf of Mexico, bringing moisture to the Great Plains.

Abnormal sea-surface temperatures have caused this low-level jet stream to continue westward and to weaken, which is preventing much-needed moisture from reaching the agriculturally critical region.

The shift in the jet stream is also allowing a southerly flow from Mexico to bring much drier air northward into the Plains.

Besides dramatically reducing precipitation for the region, the changes brought about by the abnormal sea-surface temperatures will also result in higher surface temperatures in the Plains.

"When surfaces are wet, energy from solar radiation both evaporates moisture and heats the ground," said AccuWeather.com Chief Meteorologist Elliot Abrams. "When no moisture is present, all that energy is channeled toward heating the ground, and the warm-er ground heats the lower atmosphere.

“The combination of low moisture and higher temperatures would be a crippling one-two punch for the Great Plains should these conditions persist, much like what occurred during the Dust Bowl drought."

The Dust Bowl drought

The Dust Bowl, which lasted from 1931-1939, was a severe drought that struck a wide swath of the Great Plains.

It was a catastrophic blow to the U.S. economy, which was already staggering under the weight of the Great Depression.

The Dust Bowl was the worst drought in U.S. history, eventually covering more than 75 percent of the country.

Solar radiation heating the parch-ed and blighted land caused temperatures in the region to rise to record-breaking levels.

"1936 was the hottest summer ever recorded across much of the Midwest and East," said Abrams. "Many of the single-day and monthly record-high temperatures across the eastern two-thirds of the country are from that year."

The Dust Bowl was also noted for the huge dust storms that billowed across the Great Plains and swallowed millions of acres of farmland at a time. While a Dust Bowl-level drought could occur again, it is highly unlikely that the nation will see a return of the dust storms.

"The dust storms fed off the over-plowed and over-grazed lands of the Great Plains," said Dale Mohler, AccuWeather.com expert senior meteorologist and a forecaster for the agricultural industry.

"The agricultural practices at the time, combined with a long period of drought, caused severe damage to farmland in the region. Eventually the topsoil dried up to the point where it was swept away as great clouds of choking dust that stretched for miles."

Continued Mohler, "Today's agricultural practices, such as crop rotation and improved irrigation, as well as drought-resistant hybrid crops, would likely prevent the landscape from being as ruined as it was during the 1930s.

For example, Illinois endured a terrible drought in 2005, but the state's corn yield was close to normal. However, a multiyear drought in the Great Plains would still be devastating for the nation."

The hurricane connection

"It is not a coincidence that the Dust Bowl years of the 1930s were marked by years of tremendous hurricane activity," said AccuWeather.com Hur-ricane Center Chief Forecaster Joe Bastardi.

"For example, the record-shattering 2005 hurricane season was the first to eclipse 1933 in number of tropical cyclones, and that may only have been because we didn't have satellites in the 1930s to identify the major storms that failed to reach the U.S. coast."

Hurricanes are fed by warm waters. This year's warm Atlantic waters — which are now setting up a possible major drought in the U.S. — played a major role in the 2005 season's numerous and powerful storms.

Conversely, because the Pacific has been relatively cool — another prerequisite for the return of a Dust Bowl-like drought — this year's Pacific hurricane season was tame from historical perspective.

Added Bastardi, "While we cannot yet tell how long this current pattern will last, if you trust history, then the 2005 hurricane season just may portend the return of a major drought to the Great Plains."

About AccuWeather.com

AccuWeather.com provides a portfolio of products and services through the airwaves, via the Internet, in print, and behind the scenes that benefit hundreds of millions of people worldwide. AccuWeather.com services more than 250,000 paying customers in media, business, government and institutions.and millions more through its free website. AccuWeather.com also provides content onto more than 10,000 Internet sites, including CNN Interactive, ABC's owned and operated stations, The Washington Post, and The New York Times.